What weather services have free APIs for commercial use? Out of the handful or so, which ones are easiest to tie into? Do they use "raw" HTTP requests or web services? Are there wrapper APIs for Java, .NET, Python, etc. Which have you had the best experience with?
--update
I would like something for South America ;)
--Related
If you use a Weather API that gets its information from the National Weather Service (NWS), information from that agency is within the public domain by federal law. Here are two that use data from NWS.
NOAA Protocols: SOAP Data Formats: XML, DWML National Digital Forecast Database (NDFD) Extensible Markup Language (XML) is a service providing the public, government agencies, and commercial enterprises with data from the National Weather Service’s (NWS) digital forecast database.
Weather Underground Protocols: REST Data Formats: XML Weather Underground provides real-time weather information via the Internet. Weather Underground provides weather reports for cities across the world as well as local weather reports for newspapers and Web sites.
At programmableweb.com you can search API's and Mashhups. Searching for weather API, I found 10.
World Weather Online has a free weather API. It's available for non-commercial and commercial use. You can find it at http://www.worldweatheronline.com/free-weather-feed.aspx.
The Weather Channel also has a great API. Not sure if it's commercial or not though. I would think not. You can access it at http://www.weather.com/services/xmloap.html